National Kyokushin Kai-Kan Karate Academy

Sosai Masutatsu "Mas" Oyama (1923–1994) was the legendary founder of Kyokushin Kai-kan, pioneering full-contact karate out of a desire for absolute truth in combat.

Seeking the ultimate test of human capability, Oyama retreated into extreme mountain isolation. For years, he underwent a grueling twelve-hour daily regimen—striking trees, lifting boulders, and meditating under freezing waterfalls. This intense forge hardened his body and solidified his philosophy that true karate must be rooted in raw power and practical reality.

To prove his style's effectiveness, Oyama traveled globally in the 1950s, taking on all challengers and defeating opponents with a single blow, earning the moniker "One Strike, Certain Death." He even fought raging bulls bare-handed, snapping their horns.

Officially founding Kyokushin ("Ultimate Truth") in 1964, he introduced bare-knuckle fighting and the 100-man kumite, leaving a global legacy anchored in the unbreakable Osu spirit of absolute self-discipline.